Tracks are often provided in motor vehicles such as coaches or buses, trains or aircraft for mounting a large number of passenger seats. Typically an individual seat or a row of adjacent seats are secured via legs to a carriage which is then slidably mounted upon a length of track secured to the floor of the vehicle. In this way, a number of seats or rows of seats may be installed along a length of a vehicle such that the spaces between successive seats or rows of seats may be adjusted, thereby varying the "leg room" for passengers. When the seats have been located in their desired position, the carriage may be locked to the track, typically via a spring-biased plunger engaging a recess in the track.
A significant problem with such installations is that the locking mechanism uses relatively small plungers. This presents small engaging surfaces between the plungers and the track, resulting in extremely high local forces in the event that the carriage is urged along the track against the locking mechanism, for instance in an accident. These high local forces can cause damage to the track or carriage due to buckling or breakage.
Another common problem with such installations is that different types of carriage each have an individual locking arrangement making it suitable for use with only a particular configuration of track.
In the event of an accident, it is desirable to provide a locking mechanism which acts as an energy absorber allowing controlled movement of the carriage in relation to the track. This is particularly important when passengers in a vehicle are wearing seat belts, since sudden deceleration, causes each passenger to continue moving, due to inertia, relative to the seat belt which in turn applies considerable pressure to certain parts of the body, thereby increasing the risk of injury.
It is therefore an object of the present invention to provide an improved carriage assembly.